KR20220140006A - Flex foil board connector for sensing battery voltage and temperature - Google Patents

Abstract

A sensing system for a battery includes a flex foil substrate including a first cover layer. The conductive layer defines a trace pattern comprising traces. The second cover layer defines a first opening. A conductive layer is sandwiched between the first cover layer and the second cover layer. The first opening exposes the first trace and the second trace of the trace pattern. A bus bar is attached to the first cover layer of the flex foil substrate. A temperature sensor is connected to the first trace and the second trace of the trace pattern of the first opening of the first cover layer.

Description

Flex foil board connector for sensing battery voltage and temperature

The present disclosure relates to electrical connectors, and more particularly to electrical connectors for battery systems.

The background description provided herein is for the purpose of generally presenting the context of the present disclosure. The achievements of the inventors named herein to the extent described in this background section, as well as aspects of the present technology that may not otherwise be recognized as prior art at the time of filing, are expressly or impliedly admitted as prior art to the present disclosure. doesn't happen

Hybrid vehicles include an internal combustion engine (ICE), an electric motor and a battery system. Depending on the situation, an ICE, an electric motor, or both can be used to drive the vehicle. Pure electric vehicles include an electric motor and battery system, but not ICE. Battery systems of hybrid and electric vehicles generally have higher storage capacities compared to conventional vehicles that are only propelled by ICEs.

To provide higher storage capacity, battery systems include one or more batteries connected together. Each of the batteries in turn includes one or more battery cells. A growing number of sophisticated control and monitoring techniques are used to control these battery systems. For example, during operation, additional battery parameters such as current, voltage, temperature and/or state of charge are measured and monitored. As a result, a plurality of connections may be made to each of the batteries. The operation of the battery system is adjusted based on the monitored parameters.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Patent Application Serial No. 16/805,139, filed February 28, 2020. The entire disclosure of the above-referenced applications is incorporated herein by reference.

A sensing system for a battery includes a flex foil substrate including a first cover layer. The conductive layer defines a trace pattern comprising traces. The second cover layer defines a first opening. A conductive layer is sandwiched between the first cover layer and the second cover layer. The first opening exposes the first trace and the second trace of the trace pattern. A bus bar is attached to the first cover layer of the flex foil substrate. A temperature sensor is connected to the first trace and the second trace of the trace pattern of the first opening of the first cover layer.

In other features, the bus bar is attached to the first cover layer of the flex foil substrate using a pressure sensitive adhesive (PSA). The temperature sensor includes a negative temperature coefficient (NTC) temperature sensor. The temperature sensor is attached to the first and second traces using a conductive adhesive. A protective layer is disposed over the temperature sensor and the first opening of the flex foil substrate.

In other features, the protective layer comprises a coating. The protective layer comprises a conformal coating. The battery system includes a frame, a plurality of bus bars including bus bars, and a sensing system. A plurality of bus bars are attached to the frame.

In other features, the flex foil substrate is disposed in contact with a top surface of the bus bar. The flex foil substrate includes a third trace and a second opening in a second cover layer. The third trace is connected to a bottom surface of at least another one of the plurality of bus bars through the second opening.

In other features, a third trace of the flex foil substrate is ultrasonically welded to the third trace. At least another bus bar of the bus bar and the plurality of bus bars is disposed adjacent to each other.

A connector for a battery system includes a frame and a plurality of bus bars attached to the frame. The flex foil substrate defines a trace pattern comprising a first cover layer, a second cover layer and traces and includes a conductive layer sandwiched between the first cover layer and the second cover layer. A first opening in the second cover layer exposes the first trace and the second trace of the trace pattern. A second opening in the second cover layer exposing a third trace of the trace pattern. An outer surface of a first cover layer attached to a first surface of a first bus bar of the plurality of bus bars. A third trace of the flex foil substrate in the second opening is connected to a second surface of a second bus bar of the plurality of bus bars. A temperature sensor is connected to the first trace and the second trace of the trace pattern at the first opening.

In other features, a second surface of a second bus bar of the plurality of bus bars is on a battery-facing side of the connector and a first surface of a first bus bar of the plurality of bus bars is opposite the battery-facing side of the connector is in A first bus bar of the plurality of bus bars is attached to the first cover layer of the flex foil substrate using a pressure sensitive adhesive. The temperature sensor includes a negative temperature coefficient (NTC) temperature sensor. The temperature sensor is attached to the first and second traces using a conductive adhesive. A protective layer is disposed over the temperature sensor and the first opening of the flex foil substrate.

In other features, the protective layer comprises a coating. The protective layer comprises a conformal coating.

Additional areas of applicability of the present disclosure will become apparent from the description, claims and drawings. The detailed description and specific examples are intended for purposes of illustration only, and are not intended to limit the scope of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS The present disclosure will be more fully understood from the detailed description and accompanying drawings.
1 is a plan view of an example of a battery connector assembly including a frame, bus bars, and a flex foil board according to the present disclosure;
2 is an enlarged partial plan view of an example of a battery connector assembly including a frame, bus bars, and a flex foil board in accordance with the present disclosure;
3 is a plan view of an example of a printed circuit board according to the present disclosure;
4A is a top view of an example of a printed circuit board according to the present disclosure.
4B is a side view illustrating an example of a printed circuit board connected to a flex foil substrate using a conductive adhesive in accordance with the present disclosure.
5 is a cross-sectional side view of a battery including a plurality of battery cells according to the present disclosure.
6 is a cross-sectional side view of the flex foil substrate of FIG. 2 connected to bus bars and a temperature sensor of a battery system in accordance with the present disclosure;
In the drawings, reference numbers may be reused to identify similar and/or identical elements.

As described above, the temperature of components of a battery system may be measured for several reasons. For example, the charge rate and/or the discharge rate may be adjusted based on the battery temperature to prevent damage to cells of the battery and/or improve charging efficiency. Some battery systems utilize a temperature sensor attached to a busbar using an adhesive. A wiring is routed to a controller that monitors the temperature sensor.

Flex foil substrates include a bottom layer, an intermediate layer comprising a conductive material such as copper (Cu) or aluminum (Al) defining a trace pattern comprising the traces, and a cover disposed on top of the middle layer. include layers. The traces in the flex foil substrate are used to replace the wires in wiring harnesses. The flex foil substrate can be used to connect the temperature sensor to the battery and sense the bus bar voltage.

Placement and/or attachment of a temperature sensor to a bus bar using a flex foil substrate can be problematic for several reasons. In some examples, the flex foil substrate is ultrasonically welded to the bus bars. When the temperature sensor is placed near the ultrasonic welding location to the bus bar or between the flex foil substrate and the bus bar, external forces may cause the temperature sensor to contact the bus bar, which may cause a short circuit. .

Systems and methods in accordance with the present disclosure are directed to flex foil substrates for attaching one or more temperature sensors to locations (for voltage sensing) spaced from welding locations to a bus bar. In some examples, the flex foil substrate connects temperature sensors to the top surface of the bus bars, while the flex foil substrate also connects to the bottom surfaces of the bus bars to sense voltage. This arrangement tends to protect the temperature sensor from damage and allows for accurate measurement of battery temperature. In some examples, the battery includes aluminum bus bars and the flex foil substrate includes aluminum conductive traces milled using a dry mill process.

The conductive layer of the flex foil substrate is formed using a dry milling process that creates traces of the trace pattern. A cover layer is placed over the traces. Openings are pre-cut or otherwise formed in the cover layer at locations for welding and/or at locations corresponding to temperature sensors. The temperature sensors are attached to the flex foil substrate after the application of the cover layer and the milling process. Cell voltage sensing traces and temperature sensing traces are coupled on a common flex foil substrate. The use of a flex foil substrate reduces the wires and other components required for connection. In addition to this, the use of flex foil substrates also tends to increase reliability.

Referring now to FIG. 1 , a battery connector assembly 10 for a battery system is shown. In some examples, the battery system includes two or more rows of battery cells (not shown). In some examples, the rows of battery cells include eight battery cells connected in series to the bus bars and the rows of battery cells are also connected together in series to a positive battery terminal and a negative battery terminal. As can be appreciated, the battery system described herein is for illustrative purposes only and may include other arrangements, number of cells, and/or parallel and/or series connections of battery cells, and the like.

The battery connector assembly 10 includes a frame 14, a plurality of bus bars 18-1, 18-2, ... (collectively bus bars 18) attached to the frame 14, a first flex a foil substrate 34 - 1 , and a second flex foil substrate 34 - 2 (both may be generically identified as flex foil substrate 34 ). Although the first and second flex foil substrates 34-1 and 34-2 are shown positioned below the bus bars 18, the first and second flex foil substrates 34-1 and 34-2 are 34-2) may be located and/or affixed above, below and/or above and below the substrate (eg, FIG. 2 ).

In some examples, the bus bars 18 may be connected side-by-side with the expanding portion 20 positioned therebetween as shown at 18-1 and 18-2. The expanded portion 20 may include metal that is bent or curved to allow relative movement. In other examples, the bus bars 18 may be connected end-to-end with the extended portion 21 positioned therebetween as shown at 18-3 and 18-4. In some examples, bus bars 18 include a single bus bar or a separate bus bar as shown at 18-5 and 18-6.

In some examples, one or more of the bus bars 18 include one or more holes 26 passing from one surface to the opposite surface. The opposing surface of the bus bars 18 may be attached to the flex foil substrate 34 at corresponding attachment locations 28 . In some examples, flex foil substrate 34 is attached using ultrasonic welding. One or more holes 26 may be disposed adjacent to attachment locations 28 . In some examples, adhesive may be applied to selected ones of holes 26 to provide strain relief at attachment locations 28 .

The frame 14 may include flexible tabs 22 that allow the bus bars 18 to snap-fit into the frame 14 and to be held and released as needed. In some examples, flexible tabs 22 are positioned along opposite sides of frame 14 . Additional flexible tabs 22 are disposed in a first row and a second row adjacent a central portion of frame 14 .

Referring now to FIG. 2 , the flex foil substrate 34 may be positioned such that one or more temperature sensors 58 may be attached to one or more of the plurality of bus bars 50 . The flex foil substrate 34 is disposed on top of the bus bar 50-1 and below the bus bar 50-2 (disposed adjacent to the bus bar 50-1). A temperature sensor 58 is attached to the top surface of the flex foil substrate 34 above the bus bar 50 - 1 . Similarly, a bus bar 50 - 2 is attached to the top surface of the flex foil substrate 34 . In some examples, flex foil substrate 34 is disposed below bus bar 50 - 2 and ultrasonically welded to a bottom surface of bus bar 50 - 2 as indicated at 56 .

In some examples, adhesive 54 is deposited to secure flex foil substrate 34 on flex foil substrate 34 , across bus bar 50 - 2 and on flex foil substrate 34 . In some examples, the adhesive 54 is deposited adjacent the first side and the second side of the ultrasonic weld 56 .

Referring now to FIG. 3 , an example of a flex foil substrate 34 is shown. The flex foil substrate 34 includes a conductive layer 60 and insulating layers 62 (or cover layers) on one or both sides of the conductive layer 60 . In some examples, conductive layer 60 is made of a metal such as Al or Cu and has a thickness in the range of 5 μm to 40 μm, although thicker and thinner traces may be used. In some examples, Cu having a thickness of 9 μm, 18 μm, or 35 μm, or AI having a thickness of 9 μm or 18 μm may be used. In some examples, insulating layers 62 include a film such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polyimide (PI), although other materials may be used.

) 사이에 공급된다 (feed). In some locations, portions of conductive layer 60 and/or insulating layer 62 are removed using a dry milling process to create trace patterns and/or openings. A suitable example of a dry milling process is shown and described in US Pat. No. 7,919,027, issued Apr. 5, 2011, entitled “Methods and Devices for Manufacturing of Electrical Components and Laminated Structures,” which is incorporated herein by reference in its entirety. are cited During the dry milling process, the web of the flex foil substrate moves between the milling wheel and the soft plate (

) is fed between

The soft plate includes a rotating drum and a flexible substrate attached to the rotating drum having a pattern comprising raised and non-raised portions. The substrate is attached to the drum. In some examples, the pattern is made using photolithography. A milling wheel is placed on the opposite side of the web. Raised portions of the pattern on the soft plate push the conductive layer into the milling wheel and corresponding portions of the conductive layer are removed. A similar method can be used to mill the insulating layer. The remaining conductive layer is thus intervening regions that are patterned to provide traces, pads for the fingers, and the like, and are free of the conductive layer. After milling the conductive layer, an insulating layer or coverlay layer may be disposed over the conductive layer. One or more additional milling steps may be used to create openings exposing portions of traces.

The flex foil substrate 34 includes a connection location 70 and traces 72 extending from the connection location 70 to other locations of the flex foil substrate 34 . Insulation layer 62 is removed from one side of conductive layer 60 at connection location 70 to allow external connections to traces 72 . In some examples, a plurality of fingers 74 are kiss cut within the flex foil substrate 34 and the insulating layer 62 is removed from the plurality of fingers 74 as indicated at 82 . The edges of the plurality of fingers 74 are to release a portion of the plurality of fingers 74 from the flex foil substrate 34 to allow attachment to the bus bars 18 by ultrasonic welding, conductive adhesive and/or adhesive. It is cut at 78. As shown in FIG. 3 , the plurality of fingers 74 has a rectangular shape, and the cut has a “U”-shape to release three edges of the plurality of fingers 74 . However, other shapes may be used.

In some examples, the first group of traces 80 extends into a plurality of fingers 74 positioned along one side of the flex foil substrate 34 . A second group of traces 84 extends into a plurality of fingers 74 positioned along another side of the flex foil substrate 34 . A third group of traces 86 extends to a first location 88 and a second location 90 . In some examples, temperature sensors 58 or other sensors may be disposed at first and second locations 88 , 90 or other locations. The flex foil substrate 34 may also include one or more spaced holes 92 to allow airflow through the frame 14 and the flex foil substrate 34 .

Referring now to FIGS. 4A and 4B , an external connection to a flex foil substrate is shown. In Figure 4a, a printed circuit board 150 is shown. In FIG. 4B , a printed circuit board 150 is shown attached to a flex foil board 34 . The printed circuit board 150 includes traces 154 that align with the traces 72 of the flex foil board 34 at the connection location 70 . A conductive adhesive 164 is applied between the end of the flex foil substrate 34 including the connection location 70 and the printed circuit board 150 (aligned with the traces 154 and 72 ). In some examples, the conductive adhesive 164 conducts in one direction (corresponding to the direction of applied pressure) and includes an epoxy resin. In some examples, a Delo ^® Monopox heat-curing adhesive is used. Heat and pressure are applied in a transverse direction across the printed circuit board 150 for a predetermined period to cure the adhesive. The printed circuit board 150 may include plated vias 160 to provide external connections.

Referring now to FIG. 5 , a battery system 170 includes a battery enclosure 172 surrounding a plurality of battery cells 174 . Frame 14 includes bus bars 18 (not shown in FIG. 5 ) that are attached to a plurality of battery cells 174 within battery enclosure 172 . Connector 176 provides a connection to battery system 170 for parameter sensing components and/or cell balancing (described above). Terminal connections (not shown) are also connected to the battery system 170 .

Referring now to FIG. 6 , a flex foil substrate circuit 200 includes a flex foil substrate 212 that provides a connection to a temperature sensor 214 . Although the flex foil substrate 212 is shown as including a single temperature sensor 214 connected thereto, the flex foil substrate 212 can provide connection to any number of temperature sensors 214 . In some examples, the flex foil substrate circuit 200 may be used to measure local temperatures in a battery system. For example, the flex foil substrate circuit 200 may be coupled to one or more bus bars of a battery system (and/or any other components of the battery system) as described herein.

A first bus bar 220 - 1 is attached on the bottom facing surface of the cover layer 224 of the flex foil substrate 212 . In some examples, the adhesive 226 is used to physically attach the flex foil substrate 212 to the first bus bar 220 - 1 . In some examples, adhesive 226 includes a pressure sensitive adhesive (PSA), although other types of adhesive may be used. The second bus bar 220-2 is attached on the same side of the flex foil substrate 212 at a position spaced from the first bus bar 220-1. In some examples, the flex foil substrate 212 is attached to a top surface of the first bus bar 220-1 and a bottom surface of the second bus bar 220-2. Although the first bus bar and the second bus bars 220 - 1 and 220 - 2 are shown directly adjacent to each other, the temperature sensing connection and the voltage sensing connection need not be made on the immediately adjacent bus bars.

The flex foil substrate 212 includes a conductive layer 230 . The conductive layer 230 defines a trace pattern 232 comprising a plurality of traces. In some examples, the traces of trace pattern 232 are insulated from each other and define independent electrical connections. The conductive layer 230 is sandwiched between the cover layer 224 (on the bottom) and the cover layer 238 (on the top). In some examples, the cover layers 224 and/or 238 are made of an insulating film such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polyimide (PI), although other materials may be used.

The cover layer 238 further defines one or more openings 250 on the top-facing surface of the cover layer to allow attachment of the trace pattern 232 to the traces. For example, one or more of the temperature sensors 214 can be attached to traces of the flex foil substrate 212 .

One or more openings 250 are located in areas where connections to the traces of the trace pattern 232 are needed. In some examples, the trace pattern 232 of the flex foil substrate 212 is dry milled. In general, a dry milled trace pattern includes traces with milled edges that bevel outward with respect to the opening as the distance from the underlying layer increases. In contrast, etched trace patterns will generally have etched edges that tilt inward with respect to the opening as the distance from the underlying layer increases.

For example, first and second traces 254 and 256 of trace pattern 232 are exposed at opening 250 . In some examples, the first and second traces 254 and 256 of the trace pattern 232 are routed back to a component, such as the printed circuit board 150 described above.

For example, the first conductor 260 and the second conductor 262 of the temperature sensor 214 are connected to the first trace 254 and the second trace 256 of the flex foil substrate 212 at the opening 250 . ) are attached to each. In some examples, the electrically conductive adhesive 266 connects the first and second traces 254 and 256 of the flex foil substrate 212 to the first and second conductors 260 of the temperature sensor 214 . Connect. In some examples, temperature sensor 214 includes a negative temperature coefficient (NTC) temperature sensor.

A protective layer 272 is disposed over the temperature sensor 214 and one or more openings 250 of the flex foil substrate 212 . In some examples, protective layer 272 includes a cover layer or protective coating such as those described above. In some examples, the protective coating comprises a conformal spray coating.

The flex foil substrate 212 includes an opening 282 in the cover layer 238 exposing the third trace 280 . In some examples, the third trace 280 is connected to the bottom-facing surface of the second bus bar 220 - 2 . In some examples, the third trace 280 is ultrasonically welded to the bottom-facing surface of the second bus bar 220 - 2 .

The foregoing description is merely exemplary in nature and is not intended to limit the disclosure, its application, or uses in any way. The broad teachings of this disclosure may be embodied in various forms. Accordingly, although this disclosure includes specific examples, the true scope of the disclosure should not be so limited as other modifications will become apparent upon study of the drawings, the specification and the following claims. It should be understood that one or more steps of a method may be executed in a different order (or concurrently) without changing the principles of the present disclosure. Further, although each of the embodiments has been described above as having specific features, any one or more of these features described with respect to any embodiment of the present disclosure may be used in any other implementation, even if the combination is not explicitly described. It may be implemented with features of the examples and/or in combination with features of any other embodiments. That is, the described embodiments are not mutually exclusive, and substitutions of one or more embodiments with other embodiments remain within the scope of the present disclosure.

Spatial and functional relationships between elements (eg, between modules, circuit elements, semiconductor layers, etc.) are “connected”, “engaged”, “coupled ( coupled)", "adjacent", "next to", "on top of", "above", "below" and "placed are described using various terms, including "disposed." Unless explicitly stated to be “direct,” when a relationship between a first element and a second element is described in the above disclosure, the relationship is such that other intervening elements between the first and second elements It may be a direct relationship that does not exist, but may also be an indirect relationship in which one or more intervening elements (spatially or functionally) exist between the first element and the second element. As used herein, at least one of the phrases A, B, and C is to be construed to mean logically (A or B or C), using a non-exclusive logical OR, and "at least one A , at least one B, and at least one C".

Claims (19)

A sensing system for a battery, comprising:
A flex foil substrate comprising:
a first cover layer;
a conductive layer defining a trace pattern including traces; and
A second cover layer defining a first opening, comprising:
wherein the conductive layer is sandwiched between the first cover layer and the second cover layer, and the first opening comprises the second cover layer exposing the first trace and the second trace of the trace pattern. the flex foil substrate;
a busbar attached to the first cover layer of the flex foil substrate; and
and a temperature sensor coupled to the first trace and the second trace of the trace pattern in the first opening of the first cover layer. The method of claim 1,
and the bus bar is attached to the first cover layer of the flex foil substrate using a pressure sensitive adhesive (PSA). The method of claim 1,
wherein the temperature sensor comprises a negative temperature coefficient (NTC) temperature sensor. The method of claim 1,
and the temperature sensor is attached to the first trace and the second trace using a conductive adhesive. The method of claim 1,
and a protective layer disposed over the temperature sensor and the first opening of the flex foil substrate. 6. The method of claim 5,
wherein the protective layer comprises a coating. 6. The method of claim 5,
wherein the protective layer comprises a conformal coating. frame;
a plurality of bus bars including a bus bar, wherein the plurality of bus bars are attached to the frame; and
A battery system comprising the sensing system of claim 1 . 9. The method of claim 8,
the flex foil substrate is disposed in contact with a top surface of the bus bar;
wherein the flex foil substrate includes a third trace and a second opening in the second cover layer;
and the third trace is connected to a bottom surface of at least another one of the plurality of bus bars through the second opening. 10. The method of claim 9,
and the third trace of the flex foil substrate is ultrasonically welded to the third trace. 11. The method of claim 10,
The bus bar and at least another bus bar of the plurality of bus bars are disposed adjacent to each other. A connector for a battery system, comprising:
frame;
a plurality of bus bars attached to the frame;
A flex foil substrate comprising:
a first cover layer;
a second cover layer;
a conductive layer comprising traces and defining a trace pattern sandwiched between the first cover layer and the second cover layer;
a first opening in the second cover layer exposing a first trace and a second trace of the trace pattern;
a second opening in the second cover layer exposing a third trace of the trace pattern;
an outer surface of the first cover layer attached to a first surface of a first one of the plurality of bus bars; and
the third trace of the flex foil substrate in the second opening is connected to a second surface of a second one of the plurality of bus bars; and
and a temperature sensor coupled to the first trace and the second trace of the trace pattern in the first opening. 13. The method of claim 12,
the second surface of the second bus bar of the plurality of bus bars is on a battery-facing side of the connector and the first surface of the first bus bar of the plurality of bus bars is the battery-facing side of the connector The connector, opposite the face-to-face side. 13. The method of claim 12,
wherein the first bus bar of the plurality of bus bars is attached to the first cover layer of the flex foil substrate using a pressure sensitive adhesive. 13. The method of claim 12,
wherein the temperature sensor comprises a negative temperature coefficient (NTC) temperature sensor. 13. The method of claim 12,
and the temperature sensor is attached to the first trace and the second trace using a conductive adhesive. 13. The method of claim 12,
and a protective layer disposed over the temperature sensor and the first opening of the flex foil substrate. 18. The method of claim 17,
wherein the protective layer comprises a coating. 18. The method of claim 17,
wherein the protective layer comprises a conformal coating.

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